Question

Bài 2. Tính:

3/8-3/21;7/ 2-7/10
 

Answer 1

\(\dfrac{3}{8}-\dfrac{3}{21}=\dfrac{63}{168}-\dfrac{24}{168}=\dfrac{39}{168}=\dfrac{13}{56}\\ \dfrac{7}{2}-\dfrac{7}{10}=\dfrac{35}{10}-\dfrac{7}{10}=\dfrac{28}{10}=\dfrac{14}{5}\)

Answer 2

\(\dfrac{3}{8}\) - \(\dfrac{3}{21}\) \(\dfrac{63}{168}\) - \(\dfrac{24}{168}\) = \(\dfrac{13}{56}\) ;            \(\dfrac{7}{2}\) - \(\dfrac{7}{10}\) = \(\dfrac{70}{20}\) - \(\dfrac{14}{20}\) = \(\dfrac{14}{5}\)